tpm: migrate pubek_show to struct tpm_buf

Migrated pubek_show to struct tpm_buf and cleaned up its implementation.
Previously the output parameter structure was declared but left
completely unused. Now it is used to refer different fields of the
output. We can move it to tpm-sysfs.c as it does not have any use
outside of that file.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

1 files changed, 48 insertions, 39 deletions

diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index 86f38d239476..83a77a445538 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -20,44 +20,48 @@
 #include <linux/device.h>
 #include "tpm.h"
 
-#define READ_PUBEK_RESULT_SIZE 314
+struct tpm_readpubek_out {
+	u8 algorithm[4];
+	u8 encscheme[2];
+	u8 sigscheme[2];
+	__be32 paramsize;
+	u8 parameters[12];
+	__be32 keysize;
+	u8 modulus[256];
+	u8 checksum[20];
+} __packed;
+
 #define READ_PUBEK_RESULT_MIN_BODY_SIZE (28 + 256)
 #define TPM_ORD_READPUBEK 124
-static const struct tpm_input_header tpm_readpubek_header = {
-	.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
-	.length = cpu_to_be32(30),
-	.ordinal = cpu_to_be32(TPM_ORD_READPUBEK)
-};
+
 static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
 			  char *buf)
 {
-	u8 *data;
-	struct tpm_cmd_t tpm_cmd;
-	ssize_t err;
-	int i, rc;
+	struct tpm_buf tpm_buf;
+	struct tpm_readpubek_out *out;
+	ssize_t rc;
+	int i;
 	char *str = buf;
 	struct tpm_chip *chip = to_tpm_chip(dev);
+	char anti_replay[20];
 
-	memset(&tpm_cmd, 0, sizeof(tpm_cmd));
-
-	tpm_cmd.header.in = tpm_readpubek_header;
-	err = tpm_transmit_cmd(chip, NULL, &tpm_cmd, READ_PUBEK_RESULT_SIZE,
-			       READ_PUBEK_RESULT_MIN_BODY_SIZE, 0,
-			       "attempting to read the PUBEK");
-	if (err)
-		goto out;
-
-	/*
-	   ignore header 10 bytes
-	   algorithm 32 bits (1 == RSA )
-	   encscheme 16 bits
-	   sigscheme 16 bits
-	   parameters (RSA 12->bytes: keybit, #primes, expbit)
-	   keylenbytes 32 bits
-	   256 byte modulus
-	   ignore checksum 20 bytes
-	 */
-	data = tpm_cmd.params.readpubek_out_buffer;
+	memset(&anti_replay, 0, sizeof(anti_replay));
+
+	rc = tpm_buf_init(&tpm_buf, TPM_TAG_RQU_COMMAND, TPM_ORD_READPUBEK);
+	if (rc)
+		return rc;
+
+	tpm_buf_append(&tpm_buf, anti_replay, sizeof(anti_replay));
+
+	rc = tpm_transmit_cmd(chip, NULL, tpm_buf.data, PAGE_SIZE,
+			      READ_PUBEK_RESULT_MIN_BODY_SIZE, 0,
+			      "attempting to read the PUBEK");
+	if (rc) {
+		tpm_buf_destroy(&tpm_buf);
+		return 0;
+	}
+
+	out = (struct tpm_readpubek_out *)&tpm_buf.data[10];
 	str +=
 	    sprintf(str,
 		    "Algorithm: %02X %02X %02X %02X\n"
@@ -68,21 +72,26 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
 		    "%02X %02X %02X %02X\n"
 		    "Modulus length: %d\n"
 		    "Modulus:\n",
-		    data[0], data[1], data[2], data[3],
-		    data[4], data[5],
-		    data[6], data[7],
-		    data[12], data[13], data[14], data[15],
-		    data[16], data[17], data[18], data[19],
-		    data[20], data[21], data[22], data[23],
-		    be32_to_cpu(*((__be32 *) (data + 24))));
+		    out->algorithm[0], out->algorithm[1], out->algorithm[2],
+		    out->algorithm[3],
+		    out->encscheme[0], out->encscheme[1],
+		    out->sigscheme[0], out->sigscheme[1],
+		    out->parameters[0], out->parameters[1],
+		    out->parameters[2], out->parameters[3],
+		    out->parameters[4], out->parameters[5],
+		    out->parameters[6], out->parameters[7],
+		    out->parameters[8], out->parameters[9],
+		    out->parameters[10], out->parameters[11],
+		    be32_to_cpu(out->keysize));
 
 	for (i = 0; i < 256; i++) {
-		str += sprintf(str, "%02X ", data[i + 28]);
+		str += sprintf(str, "%02X ", out->modulus[i]);
 		if ((i + 1) % 16 == 0)
 			str += sprintf(str, "\n");
 	}
-out:
+
 	rc = str - buf;
+	tpm_buf_destroy(&tpm_buf);
 	return rc;
 }
 static DEVICE_ATTR_RO(pubek);